Solid state light emitting devices, such as light emitting diodes (LEDs), are attractive candidates for replacing conventional light sources such as incandescent, halogen, and fluorescent lamps. LEDs have substantially longer lifetimes than all three of these types of conventional light sources. In addition, some types of LEDs now have higher conversion efficiencies than fluorescent light sources and still higher conversion efficiencies have been demonstrated in laboratories. Finally, LEDs contain no mercury or other potentially dangerous materials, therefore, providing various safety and environmental benefits.
A troffer is a light fixture resembling an inverted trough that is either recessed in, or suspended from, the ceiling. Troffers are typically designed to emit light using fluorescent lighting tubes. The fluorescent tubes emit light along the entire length of the troffer to produce a focused light distribution pattern. However, fluorescent lighting tubes may be expensive, require a warm up period, and produce flicker that is undesirable.
More recently, solid state light emitting devices have been used to replace fluorescent lamps conventionally used in troffer assemblies. LEDs are attractive candidates for replacing fluorescent lighting tubes because LEDs have no warm up time, are long lasting and power efficient, and do not flicker. Troffer assemblies with LED light sources are sometimes referred to as linear LED modules, and conventional linear LED modules have been widely utilized in the global troffer market.
Typically, conventional linear LED designs utilize rigid FR4 or Metal Core Printed Circuit Board (MCPCB) substrates coated with a white solder mask for light reflection and diffusion. Such boards are commonly mounted on rigid metal plates (such as aluminum) with reflective sides for directing light down into a diffuser lens and out of the metal troffer tube. The metal plate sometimes also doubles as a heat sink.
The conventional linear LED assembly can be expensive, heavy, and overly complex. It is therefore difficult to design a linear LED assembly that is both cost efficient, lightweight, and is not overly complex.